Lifting-jack



(HodeL) J. F. MQOORMIGK.

Lifting Jack.

No. 229,727. Patented July 6, 1880.

I NVENTOR I aW/Wmo/V ATTORNEYS.

N. PETERS, PHOTO-LITHOGR UNITED STATES PATENT OFFICE.

JAMES F. MCCORMICK, OF LOUISVILLE, KENTUCKY.

LlFTlNG-JAC K.

SPECIFICATION forming part of Letters Patent No. 229,727, dated July 6, 1880.

Application filed April 7, 1880.

To all whom it may concern:

Be itknown that I, JAMES F. McGoRMIoK, of Louisville, in the county of Jefferson and State of Kentucky, have invented a new and Improved Lifting-Jack, of which the following is a specification.

The object of this invention is to provide a simple and eifective double-action lifting-j ack; and the invention consists of a hollow racktoot-hed column, in which moves a vertical working-bar that carries pivoted on its head a bifurcated lever, within each end of which lever are pivoted curved swinging pawls that engage alternately with the rack-teeth of the column as the lever is operated, and thereby elevate the working-bar.

The drawing represents a perspective view of the, device with a portion broken away to better exhibit other parts.

A represents the column, supported on base B, provided with rack-teeth a a on opposite faces, and having a vertical slot, 1), in one face, extending from and through the base B up to the rack-teeth a, a.

C is the working-bar, set within the column A provided with a lug, c, that projects laterally from its lower end through the slot b, and is designed to be engaged beneath objects that are too low for the engagement of the head of the jack for the purpose of raising them, and also prevents the said bar C from being raised too high and prevents it from turning around. Said bar C is also provided with a rectangular head, d. The bifurcated lever D embraces (ModeL) and is pivoted to this head d, and has pivoted within it, on either side of the head d of the working-bar C, a curved depending dog or pawl, E, whose lower ends engagein the rackteeth a a of the column A.

As the lever D is reciprocated up and down by power applied to the handle f thereof, the dogs or pawls E E alternately engage in the rack-teeth (t a, and thereby raise the workin bar C, while on disengaging said pawls E E from the teeth a a the bar C will fall, so that its head (I will rest upon the top of the column A. These dogs or pawls E E are so curved that they require no springs to hold them engaged with the rack-teeth a a when the jack is in a vertical position.

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1. The combination, with the stationary column A, having upwardly-inclined teeth on opposite sides, of the movable bar C, having lug c and head d, the lever D, and the downwardly-acting pawls E E, pivoted to opposite arms of said lever, as shown and described.

2. in a lifting-jack, the combination, with the hollow column A, provided with rack-teeth a a and slot b, of the working-bar C, provided with lug 0 and head 61, substantially as herein shown and described.

JAMES FRANCES MCCORMICK.

Witnesses:

ROBERT MOALEESE, JOHN F. HAIN. 

